A small, uncontrolled study in the journal Lancet Psychiatry suggests that psilocybin, an ingredient in hallucinogenic mushrooms, relieved depression symptoms for up to three months in seven of 12 participants with unipolar depression that had not responded to at least two antidepressant medications.

Psilocybin has a different mechanism of action than typical treatments for depression. It activates 5HT2A serotonin receptors.

The participants, who had moderate to severe depression, were given two oral doses of psilocybin, a low dose (10mg) to establish the safety of the intervention, and a higher dose (25mg) seven days later. Psychedelic effects (anxiety, confusion, nausea, and headache) peaked within two to three hours and had dissipated by six hours after the intervention.

Depression began to improve within 24 hours after the 25mg dose. Depression symptoms were significantly improved by one week after the intervention. Eight of the 12 participants had a complete remission of their depression after one week, and this lasted the full three months in five participants. By the end of the three months, a total of seven of the 12 participants met the criteria for response to psilocybin.

The study’s authors, led by Robin L. Carhart-Harris, suggest that their preliminary results warrant more systematic investigation of psilocybin, but because there was no comparison group in this study, a large placebo effect cannot be ruled out.

Although the editors of BipolarNews.org have made every effort to report accurate information, much of the work referenced here is in abstract or pre-publication form, and may not have received proper review by the scientific community at this time. Patients should consult with their physicians about any treatment decisions. Physicians should consult the peer-reviewed literature.